Creating brokers

Creating a broker by using the Knative CLI
Creating a broker by annotating a trigger
Creating a broker by labeling a namespace
Deleting a broker that was created by injection
Creating a broker by using the web console
Creating a broker by using the Administrator perspective
Next steps
Additional resources

Knative provides a default, channel-based broker implementation. This channel-based broker can be used for development and testing purposes, but does not provide adequate event delivery guarantees for production environments.

If a cluster administrator has configured your OpenShift Serverless deployment to use Apache Kafka as the default broker type, creating a broker by using the default settings creates a Knative broker for Apache Kafka.

If your OpenShift Serverless deployment is not configured to use the Knative broker for Apache Kafka as the default broker type, the channel-based broker is created when you use the default settings in the following procedures.

Creating a broker by using the Knative CLI

Brokers can be used in combination with triggers to deliver events from an event source to an event sink. Using the Knative (kn) CLI to create brokers provides a more streamlined and intuitive user interface over modifying YAML files directly. You can use the kn broker create command to create a broker.

Prerequisites

The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster.
You have installed the Knative (kn) CLI.
You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform.

Procedure

Create a broker:
```
$ kn broker create <broker_name>
```

Verification

Use the kn command to list all existing brokers:

$ kn broker list

Example output

NAME      URL                                                                     AGE   CONDITIONS   READY   REASON
default   http://broker-ingress.knative-eventing.svc.cluster.local/test/default   45s   5 OK / 5     True

Optional: If you are using the OpenShift Container Platform web console, you can navigate to the Topology view in the Developer perspective, and observe that the broker exists:

Creating a broker by annotating a trigger

Brokers can be used in combination with triggers to deliver events from an event source to an event sink. You can create a broker by adding the eventing.knative.dev/injection: enabled annotation to a Trigger object.

If you create a broker by using the eventing.knative.dev/injection: enabled annotation, you cannot delete this broker without cluster administrator permissions. If you delete the broker without having a cluster administrator remove this annotation first, the broker is created again after deletion.

Prerequisites

The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster.
Install the OpenShift CLI (oc).
You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform.

Procedure

Create a Trigger object as a YAML file that has the eventing.knative.dev/injection: enabled annotation:

apiVersion: eventing.knative.dev/v1
kind: Trigger
metadata:
  annotations:
    eventing.knative.dev/injection: enabled
  name: <trigger_name>
spec:
  broker: default
  subscriber: (1)
    ref:
      apiVersion: serving.knative.dev/v1
      kind: Service
      name: <service_name>

1	Specify details about the event sink, or subscriber, that the trigger sends events to.

Apply the Trigger YAML file:
```
$ oc apply -f <filename>
```

Verification

You can verify that the broker has been created successfully by using the oc CLI, or by observing it in the Topology view in the web console.

Enter the following oc command to get the broker:

$ oc -n <namespace> get broker default

Example output

NAME      READY     REASON    URL                                                                     AGE
default   True                http://broker-ingress.knative-eventing.svc.cluster.local/test/default   3m56s

Optional: If you are using the OpenShift Container Platform web console, you can navigate to the Topology view in the Developer perspective, and observe that the broker exists:

Creating a broker by labeling a namespace

Brokers can be used in combination with triggers to deliver events from an event source to an event sink. You can create the default broker automatically by labelling a namespace that you own or have write permissions for.

Brokers created using this method are not removed if you remove the label. You must manually delete them.

Prerequisites

The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster.
Install the OpenShift CLI (oc).
You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform.
You have cluster or dedicated administrator permissions if you are using Red Hat OpenShift Service on AWS or OpenShift Dedicated.

Procedure

Label a namespace with eventing.knative.dev/injection=enabled:

$ oc label namespace <namespace> eventing.knative.dev/injection=enabled

Verification

You can verify that the broker has been created successfully by using the oc CLI, or by observing it in the Topology view in the web console.

Use the oc command to get the broker:

$ oc -n <namespace> get broker <broker_name>

Example command

$ oc -n default get broker default

Example output

NAME      READY     REASON    URL                                                                     AGE
default   True                http://broker-ingress.knative-eventing.svc.cluster.local/test/default   3m56s

Optional: If you are using the OpenShift Container Platform web console, you can navigate to the Topology view in the Developer perspective, and observe that the broker exists:

Deleting a broker that was created by injection

If you create a broker by injection and later want to delete it, you must delete it manually. Brokers created by using a namespace label or trigger annotation are not deleted permanently if you remove the label or annotation.

Prerequisites

Install the OpenShift CLI (oc).

Procedure

Remove the eventing.knative.dev/injection=enabled label from the namespace:
```
$ oc label namespace <namespace> eventing.knative.dev/injection-
```
Removing the annotation prevents Knative from recreating the broker after you delete it.

Delete the broker from the selected namespace:

$ oc -n <namespace> delete broker <broker_name>

Verification

Use the oc command to get the broker:

$ oc -n <namespace> get broker <broker_name>

Example command

$ oc -n default get broker default

Example output

No resources found.
Error from server (NotFound): brokers.eventing.knative.dev "default" not found

Creating a broker by using the web console

After Knative Eventing is installed on your cluster, you can create a broker by using the web console. Using the OpenShift Container Platform web console provides a streamlined and intuitive user interface to create a broker.

Prerequisites

You have logged in to the OpenShift Container Platform web console.
The OpenShift Serverless Operator, Knative Serving and Knative Eventing are installed on the cluster.
You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform.

Procedure

In the Developer perspective, navigate to +Add → Broker. The Broker page is displayed.
Optional. Update the Name of the broker. If you do not update the name, the generated broker is named default.
Click Create.

Verification

You can verify that the broker was created by viewing broker components in the Topology page.

In the Developer perspective, navigate to Topology.
View the mt-broker-ingress, mt-broker-filter, and mt-broker-controller components.

Creating a broker by using the Administrator perspective

Brokers can be used in combination with triggers to deliver events from an event source to an event sink. Events are sent from an event source to a broker as an HTTP POST request. After events have entered the broker, they can be filtered by CloudEvent attributes using triggers, and sent as an HTTP POST request to an event sink.

Prerequisites

The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster.
You have logged in to the web console and are in the Administrator perspective.
You have cluster administrator permissions on OpenShift Container Platform, or you have cluster or dedicated administrator permissions on Red Hat OpenShift Service on AWS or OpenShift Dedicated.

Procedure

In the Administrator perspective of the OpenShift Container Platform web console, navigate to Serverless → Eventing.
In the Create list, select Broker. You will be directed to the Create Broker page.
Optional: Modify the YAML configuration for the broker.
Click Create.

Next steps

Configure event delivery parameters that are applied in cases where an event fails to be delivered to an event sink.

Creating a broker by using the Knative CLI

Creating a broker by annotating a trigger

Creating a broker by labeling a namespace

Deleting a broker that was created by injection

Creating a broker by using the web console

Creating a broker by using the Administrator perspective

Next steps

Additional resources